2002 YAMAHA YZ125LC clutch

2-9
SPECMAINTENANCE SPECIFICATIONS
NOTE:
1. First, tighten the ring nut approximately 38 Nm (3.8 m•kg, 27 ft•lb) by using the ring nut wrench,
then loosen the ring nut one turn.
2. Retighten the ring nut 7 Nm (0.7 m•kg, 5.1 ft•lb).
Part to be tightened Thread size Q'tyT ightening torqueNm m•kg ft•lb
Handle crown and outer tube M 8 ×1.25 4 23 2.3 17
Under bracket and outer tube M 8 ×1.25 4 20 2.0 14
Handle crown and steering shaft M24 ×1.0 1 145 14.5 105
Handlebar holder (upper) M 8 ×1.25 4 28 2.8 20
Steering ring nut M28 ×1.0 1 Refer to NOTE
Front fork and cap bolt M48 ×1.0 2 30 3.0 22
Front fork and base valve M30 ×1.0 2 55 5.5 40
Cap bolt and damper rod (front fork) M12 ×1.25 2 29 2.9 21
Bleed screw (front fork) and cap bolt M 5 ×0.8 2 1 0.1 0.7
Front fork and protector M 6 ×1.0 6 10 1.0 7.2
Cable guide (front brake hose) and guide stayM 5 ×0.8 1 4 0.4 2.9
Front fork and brake hose holder M 6 ×1.0 2 10 1.0 7.2
Front fork and hose cover M 8 ×1.25 1 16 1.6 11
Front fork and hose cover M 6 ×1.0 1 7 0.7 5.1
Throttle cable cap M 4 ×0.7 2 1 0.1 0.7
Front brake master cylinder and bracket M 6 × 1.0 2 9 0.9 6.5
Brake lever (bolt) M 6 ×1.0 1 6 0.6 4.3
(nut) M 6 ×1.0 1 6 0.6 4.3
Brake lever position locknut M 6 ×1.0 1 5 0.5 3.6
Clutch lever (bolt) M 6 ×1.0 1 2 0.2 1.4
Clutch lever holder M 5 ×0.8 2 4 0.4 2.9
Front brake master cylinder cap M 4 ×0.7 2 2 0.2 1.4
Front brake hose union bolt (master cylinder)M10 ×1.25 1 30 3.0 22
Front brake hose union bolt (caliper) M10 ×1.25 1 30 3.0 22
Front brake caliper and front fork M 8 ×1.25 2 23 2.3 17
Grip cap upper and lower M 6 ×1.0 2 4 0.4 2.9
Brake caliper (front and rear) and pad pin plugM10 ×1.0 1 3 0.3 2.2
Brake caliper (front and rear) and pad pin M10 ×1.0 1 18 1.8 13
Brake caliper (front and rear) and bleed screwM 8 ×1.25 1 6 0.6 4.3
Front wheel axle and nut M16 ×1.5 1 105 10.5 75
Front wheel axle holder M 8 ×1.25 4 23 2.3 17
Front brake disc and wheel hub M 6 ×1.0 6 12 1.2 8.7
Rear brake disc and wheel hub M 6 ×1.0 6 14 1.4 10
Brake pedal mounting M 8 ×1.25 1 26 2.6 19
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5NY-9-30-2A 5/24/01 8:03 PM Page 10

2-15
SPECCABLE ROUTING DIAGRAM
1Cable guide
2Radiator breather hose
3Ignition coil
4CDI magneto lead
5Clutch cable
6CDI unit band
7CDI unit
8Wireharness
9High tension cord
0CDI unit bracket
qClampAPass the cluch cable into
the cable guide.
BPass the clutch cable over
the radiator hose.
CPass the wireharness between
the convexites of the CDI unit
band.
DClamp the high tension cord on
the upper part of the frame
gusset at its protecting tube.
EPass the ground lead between
the ignition coil and bracket and
fasten it together with the
ignition coil. Make sure that the
ground lead does not contact
the ignition coil and bracket.
FPass the radiator breather
hose at the rear of the radiator
hose.
GCut the clamp end to be flush
with CDI unit side.HFit the CDI unit band over
the CDI unit bracket till it
stops.
IClamp the wireharness on the
CDI unit with the clamp ends
upward.
5NY-9-30-2B 5/23/01 8:03 PM Page 30

2-17
SPECCABLE ROUTING DIAGRAM
AInstall the brake hose so that its pipe portion
directs as show and lightly touches the
projection on the master cylinder.
BPass the “ENGINE STOP” button lead in
the middle of the clutch holder.
CPass the clutch cable in front of the throttle
cable.
DClamp the “ENGINE STOP” button lead to
the handlebar to 3 clicks.
EPass the brake hose in front of the number
plate and through the cable guide.
FCross the clutch cable and throttle cable
over the number plate boss. 1Brake hose
2Master cylinder
3“ENGINE STOP” button lead
4“ENGINE STOP” button
5Throttle cable
6Clutch cable
7Clamp
8Cable guide
5NY-9-30-2B 5/23/01 8:03 PM Page 34

3-1
MAINTENANCE INTERVALS
INSP
ADJ
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
EC310052
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the required
maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in maintaining
and lubricating your machine, consult your Yamaha dealer.
Item Remarks
PISTON
Inspect and clean
Inspect crack
ReplaceRemove carbon
PISTON RING
InspectCheck ring end gap
Replace
PISTON PIN, SMALL END BEARING
Inspect
Replace
CYLINDER HEAD
Inspect and cleanRemove carbon
RetightenCheck gasket
CYLINDER
Inspect and clean
Inspect score marks
ReplaceInspect wear
YPVS
Inspect and clean
CLUTCHInspect housing, friction
Inspect and adjustplate, clutch plate and
Replacespring
TRANSMISSION
Replace oilYamalube 4 (10W-30) or
InspectSAE 10W-30 SE motor oil
Replace bearing
SHIFT FORK, SHIFT CAM, GUIDE BAR
InspectInspect wear
ROTOR NUT
Retighten
MUFFLER
Inspect
Clean
CRANK
Inspect and clean
CARBURETOR
Inspect, adjust and clean
SPARK PLUG
Inspect and clean
Replace
DRIVE CHAIN Use chain lube
Lubricate, slack, alignmentChain slack: 40~50 mm
Replace(1.6~2.0 in)
After
break-
inEvery
raceEvery
thirdEvery
fifthAs re-
quired
3
5NY-9-30-3A 5/23/01 8:24 PM Page 2

3-4
PRE-OPERATION INSPECTION AND MAINTENANCE
INSP
ADJ
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EC321000
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
Coolant Check that coolant is filled up to the radiator filler cap.
Check the cooling system for leakage.P3-5~9
Fuel Check that a fresh mixture of oil and gasoline is filled in
the fuel tank. Check the fuel line for leakage.P1-12
Transmission oil Check that the oil level is correct. Check the crankcase
for leakage.P3-12~14
Gear shifter and clutch Check that gears can be shifted correctly in order and
that the clutch operates smoothly.P3-9
Throttle grip/Housing Check that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and P3-10~11
housing, if necessary.
Brakes Check the play of front brake and effect of front and
rear brake.P3-17~23
Chain Check chain slack and alignment. Check that the chain
is lubricated properly.P3-24~26
Wheels Check for excessive wear and tire pressure. Check for
loose spokes and have no excessive play.P3-34~35
Steering Check that the handlebar can be turned smoothly and
have no excessive play.P3-35~36
Front forks and Check that they operate smoothly and there is no oil
rear shock absorber leakage.P3-26~33
Cables (wires) Check that the clutch and throttle cables move smooth-
ly. Check that they are not caught when the handlebars —
are turned or when the front forks travel up and down.
Muffler Check that the muffler is tightly mounted and has no
cracks.P3-15~16
Sprocket Check that the driven sprocket tightening bolt is
not loose.P3-24
Lubrication Check for smooth operation. Lubricate if necessary. P3-37
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P1-16
Lead connectors Check that the CDI magneto, CDI unit, and ignition coil
are connected tightly.P1-6
Settings Is the machine set suitably for the condition of the
racing course and weather or by taking into account the
P7-1~24
results of test runs before racing? Are inspection and
maintenance completely done?
5NY-9-30-3A 5/23/01 8:24 PM Page 14

3-9
INSP
ADJ
CLUTCH ADJUSTMENT
NOTE:
9Do not apply pressure more than specified
pressure.
9Radiator should be filled fully.
4. Inspect:
9Pressure
Impossible to maintain the specified pres-
sure for 10 seconds Repair.
9Radiator 1
9Radiator hose joint 2
Coolant leakage Repair or replace.
9Radiator hose 3
Swelling Replace.
2. Adjust:
9Clutch lever free play
EC359020
CLUTCH ADJUSTMENT
1. Check:
9Clutch lever free play a
Out of specification Adjust.
NOTE:
9Make minute adjustment on the lever side
using the adjuster 3.
9After adjustment, check proper operation of
clutch lever.
Clutch lever free play a a
:
8~13 mm (0.31~0.51 in)
Clutch lever free play adjustment steps:
9Loosen the locknut 1.
9Turn the adjuster 2until free play ais
within the specified limits.
9Tighten the locknut.
5NY-9-30-3A 5/23/01 8:24 PM Page 26

3-37
LUBRICATION
INSP
ADJ
EC36a042
LUBRICATION
To ensure smooth operation of all components,
lubricate your machine during setup, after break-
in, and after every race.
1All control cable
2Clutch lever pivot
3Shift pedal pivot
4Footrest pivot
5Throttle-to-handlebar contact
6Drive chain
7Throttle roller sliding surface
8Tube guide cable winding portion
9Throttle cable end
0Clutch cable endÅUse Yamaha cable lube or equivalent on
these areas.
ıUse SAE10W-30 motor oil or suitable chain
lubricants.
ÇLubricate the following areas with high quali-
ty, lightweight lithium-soap base grease.
cC
Wipe off any excess grease, and avoid get-
ting grease on the brake discs.
A
A
CC
AB
AA
5NY-9-30-3B 5/23/01 8:34 PM Page 38

4-30
ENGCLUTCH AND PRIMARY DRIVEN GEAR
Extent of removal Order Part name Q’ty Remarks
CLUTCH PLATE AND
FRICTION PLATE REMOVAL
Preparation for Drain the transmission oil.
Refer to “TRANSMISSION OIL REPLACE-
removalMENT“ section in the CHAPTER 3.
Bolt (brake pedal) Shift the brake pedal downward.
Clutch cable Disconnect at engine side.
1 Clutch cover 1
2 Screw (clutch spring) 5
3 Clutch spring 5
4 Pressure plate 1
5 Push rod 1
6 Plain washer 2
7 Bearing 1
8 Friction plate 8
9 Clutch plate 7
Extent of removal:1Clutch plate and friction plate removal
EC490000
CLUTCH AND PRIMARY DRIVEN GEAREC498000
CLUTCH PLATE AND FRICTION PLATE
1
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
5NY-9-30-4B 5/23/01 8:48 PM Page 26